Так в чем разница? В шапке темы написано:
« Транзиент или транзиент атаки – начальный импульс энергии перкуссионных (ударных) звуков, например, треугольника, барабана, удара молоточка по струне фортепиано. От себя добавлю, что и каждый индивидуальный “щипок” при гитарном переборе тоже подходит под это понятие.»
А вот что по поводу IR говорится в мануле REW:
The impulse response is in essence a recording of what it would sound like in the room if you played an extremely loud, extremely short click - something like the crack of a pistol shot. The reason for measuring the impulse response (by more subtle means than firing a gun in the room) is that it completely characterises the behaviour of the system consisting of the speaker(s) that were measured and the room they are in, at the point where the measurement microphone is placed. An important property of an impulse, not intuitively obvious, is that it if you break it up into individual sine waves you find that it contains all frequencies at the same amplitude. Strange but true. This means that you can work out a system’s frequency response by determining the frequency components that make up its impulse response.
Выделение мое